How long does it take to culture rotifers?
- Thread starter cliff92
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WestOhooligan
Community Member
Doesn't take long at all. If you buy a viable batch and feed them right. I used to thin daily once I hit the 5 gallon mark. If the culture gets too crowded, the females stop producing, and that's usually when the crash starts. For better info, go to www.mbisite.org
It's the site for the Marine Breeders Initiative. There are many threads on culturing rotifers.
It's the site for the Marine Breeders Initiative. There are many threads on culturing rotifers.
WestOhooligan
Community Member
I used to look for a density of about 50/mL. I had one of those vials left over from an old API test kit. I'd pull about a mL and just sort of guesstimate/count. It help when doing a water chance I would basically seive the Rotifers a gallon at a time and feed the excess to my reef tank. They will typically double every 24 hours.
arichard
New Member
Using a scope is the most accurate way to count your rotifer populations. You don't need a scope quite as power as one with 2000x magnification. One with a magnification of 20x-40x to count them should work (usually a stereo microscope is in that range). When you count them it is far easier count a dilution of the population that estimates the population vs counting every rotifer out individually. Below is a method I've used to track my cultures in the past. Worked pretty well.
Ex. You have a 5 gallon bucket full of rotifers and don't know how many are in it.
Supplies: Clean saltwater (no rotifers in it), Microscope, graduated cylinder (10 mL volume), 1 mL plastic pipettes, 50 mL beaker, microscope, a well slide or Sedgwick-Rafter slide (as long as the slide has a depression volume of 1 mL).
1) Start by measuring 27 mL of clean saltwater in the graduated cylinder and add it to the 50 mL beaker.
2) Take (3) 1 mL samples from your rotifer bucket with the 1 mL pipette and add it to your 50 mL beaker. Take the samples from random locations in the rotifer bucket just under the surface to ensure an accurate subsample.
3) Set up the well slide on the microscope with a magnification of 20x-40x.
4) Take the pipette and randomly mix up the rotifers samples in the 50 mL beaker. Don't mix in a circular motion because all the rotifers will collect in one spot. You want them to be randomly distributed throughout your beaker to draw an accurate subsample each time.
5) Draw 1 mL from your 50 mL beaker and put it on the slide to count.
6) After making your count repeat steps 4 and 5 two more times so you have three counts of rotifers from 50 mL beaker sample.
7) Take the average and you have figured out the estimated number of rotifers per mL in the 50 mL beaker that has been diluted 10X.
8) Take this average number you've calculated and multiply by your dilution (in this case 10x). This gives you the estimated number of rotifers per mL in your rotifer culture bucket.
9) Multiply that number by the total volume of your rotifer bucket (in mL) to give you the number of rotifers in your culture bucket.
**You can change your dilution according to the number of rotifers you see on the slide. I usually start with 27 mL of clean saltwater + 3 mL of rotifer water which creates a 10x dilution of the rotifer culture. That's usually sufficient for cultures less than 5 gallons but you may want to increase or decrease you dilution based on the number of rotifers you see in the scopes field of view. 5-30 rotifers per view field will give you a pretty accurate estimation. Any more in the view field you'll have difficulty counting and it will throw off your estimate. Less than 5 roitfers per view field the dilution might be too large and give you an inaccurate estimate.**
Example of the math/calculations
Dilution: 27 mL of clean saltwater + 3 mL of rotifer sample = 30 mL of volume of diluted sample.
30 mL of volume of diluted sample divided by 3 mL of rotifer sample = 10x dilution
Count #1: 21 roitfers Count #2: 25 roitfers Count #3: 29 roitfers Average count = 25 rotifers/mL in 10x diluted sample
25 rotifers/mL in 10x diluted sample X 10x dilution= 250 rotifers/mL in your rotifer culture bucket.
~4.5 gallons in your culture bucket = 3785 mL/gallon X 4.5 gallons in culture bucket= 17032.5 mL in you culture bucket.
250 rotifers/mL in your rotifer culture bucket X 17032.5 mL in your culture bucket = 4,258,125 rotifers in the culture bucket.
If this is something you check daily you can put your population numbers into an Excel Spreadsheet and it will help with tracking health and progress of your rotifer culture.
Hope this info is helpful. By no means is this the only way to count rotifers, nor is it necessarily the best way, just a way I've personally done it in the past with pretty good success.
